Pump



Feb, 7, E95@ W. E. ARMsTRoNc-a PUMP 2 Sheets-Sheet 1 Filed May 2, 1945 Feb.. E95@ w. E. ARMSTRONG 2,49668 PUMP Filed May 2, 1945 2 Sheets-Sheet 2 Patented Feb. 7, 1959 PUMP Werner E. Armstrong, Milwaukee,l Wis., assigner to Briggs & Stratton Corporation, Milwaukee, Wis., a corporation of Delaware Application May 2, 1945, Serial No'. 591,453

Claims. l

This invention relates to pumps and has particular reference to fuel pumps of the type used on internal combustion engines.

One of the objects of the present invention resides in the provision of an inexpensive improved fuel pump which is especially suited for use with small portable internal combustion engines.

More speciiically it is an object of this inven tion to provide a fuel pump of the character described with a valve chamber formed as an integral part of the uid passageway in the body of the pump and in which the check valves are readily detachably mounted.

Another object of this invention resides in the provision of a check valve of novel unitary design which is especially suited for diaphragm operated fuel pumps.

A further object of this invention resides in the provision of a novel lost motion connection between the operating lever and the diaphragm of a fuel pump of the character described.

With the above and other objects in view, which will appear as the description proceeds, this invention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly dened by the appended claims, it being understood that such changes in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claims'.

The accompanying drawings illustrate one complete example of the physical embodiment of the invention constructed in accordance with the best mode so far devised for the practical application of the principles thereof, and in which:

Figure 1 is a cross sectional view through the fuel pump of this invention;

Figure 2 is a sectional view through the valve chamber of the pump taken on the plane of the line 2-2 .of Figure 1;

Figure 3 is a perspective view of a portion of the pump body showing the entrance to the valve chamber and illustrating the various elements constituting the valve assembly of the pump with the parts shown in the order of their assembly; and

Figure 4 is a perspective view of one of the check valves of this invention with the parts thereof disassambled but in their proper positional relationship with respect to the valve body.

Referring now more particularly to the accompanying drawings in which like numerals indicate like parts throughout the several views, the numeral 5 generally designates the body of the fuel pump of this invention and which is formed in two sections 6 and 'I secured together by means of screws B and having a exible diaphragm 9 confined therebetween.

The Section 6' is adapted to be secured against the side wall IIJ of an internal combustion engine and has its interior hollow to accommodate diaphragm operating mechanism indicated generally by the numeral. II. The meeting faces of vthe body sections which conne the diaphragm therebetween are recessed in a more or less conventional manner to dene a diaphragm operating chamber I2 so as to permit operating clearance for the diaphragm when the same is iiexed in opposite directions in the suction and pressure strokes of. the pump.

Flexing of the diaphragm is accomplished by means of a lever I3. having a bell-crank shape withv the arm I4 of the lever projecting. substantially horizontally out of the body section 6 for engagement of its end. portion I5 with a cam I6 driven by aA rotating shafty of' the engine.. The inner end of the arm I4-y inside the pump section 6 is pivotally connected to the pump body as at I1, and the arm I8 ofy the lever extends upwardly from the pivot substantially at right angles to the arm I4 toward a stem I9 secured at one end to the diaphragm and extending axially' therefrom into the hollow interior of the body section 6.

The stem I94 has a diametrically milled slot 20 through its free end and extending close to the diaphragm to receive the upper extremity 2l. of the lever arm I8. A pin 2'2 extending through the stem' on an axis transverse to the plane of the kmilled slot 20 is received in a substantially horizontal bean shapedslot 23 cut into the extremity 2| of the lever arm to provide a lost motion driving connection between the lever and the diaphragm.

A compression spring 24 coaxial with thestem I9 and confined between its outer free end and the wall of the body section E adjacent to the engine wall Il) yieldingly urges the diaphragm toward the body section T and has suflicient expansive force as to eiect the pressure stroke of the pump; Motion of the diaphragm toward the body section l solely in response to the compression spring 2'4 in the compression stroke thus is limited by engagement of the cross pin 22 with the right hand endv of the slot 231 in the lever arm I'8'. Hence, it will' be noted that the pressure stroke of thev pump is eiectedl impositively.

The return or suction stroke of the pump takes place upon rotation of the cam to a position opposite to that shown in Figure 1 and is eiecttained in engagement with the cam I6 throughout its entire period of rotation by means of a separate compression spring 25 reacting between the upper end of the lever arm adjacent to the stem IS of the diaphragm and the wallof the pump adjacent to the engine wall I U and on a line substantially parallel with the axis of the stem and its spring 24.

The spring 25 `preferably has less force than the compression spring 24 ,and causes the lever to follow the diaphragm in its spring propelled pressure stroke so as to limit clicking noises at its lost motion connection `with the diaphragm stem.

It will be seen, therefore, that the lever lll is oscillated on its pivot 'by rotation of the cam .IB and that such oscillation of the lever is translated into alternative impositive pressure and positive suction pulsations for operation of the Dump These alternate pressure and suction pulsations are utilized to establish a fiow of fuel from erably interposed. between the plate and the bottom of the mouth for a purpose shortly to be described. The plate 42 also has a central aperture it therein coaxial with the core 3B to provide communication between it and the sediment bowl.

A pair of check valves 4l and 48 are confined within the core 3B and are retained in positions at the opposite ends of the core by means of a compression spring 49 reacting between the valves to yieldingly urge the inlet valve @l iirmly against the gasket 45 and the outlet valve 48 against a gasket 5U interposed between the outlet valve and the shoulder il at the inner end of the core 38.

The valves are thus readily detachably sealed in the core 38 against the possibilityr of leakage of fluid therepast and it will, consequently, be noted that the core 38 thus provides a valve chamber forming an integral part of the fluid passageway comprising the cores 38, 39, and 40 and leading to the outlet 3| of the pump.

The inlet and outlet valves operate in a conventional manner. The inlet valve 4l has a disc 5l responsive to reduced pressure within the valve chamber for establishing communication between the interior of the sediment bowl and valve chamber, while the outlet valve 48 likewise has a disc 5l but its disc responds only to increased pressure in the valve chamber so that iiuid therein is forced to the outlet 3l of the pump on the a supply thereof into and through the body section 1 to a carburetor or the like and for this purpose the body section l is provided with inlet and outlet ports 3B and 3l respectively.

In the present instance the inlet port 30 enters the side of the body section 1 remote from the diaphragm and opens to the bottom face 3E of the body section l' through a short angular passageway 33 to directiuel entering the pump body into a sediment bowl 34 secured to the body section 'l with its rim seated against the face 32. The conventional strap 35 passing beneath the sediment bowl and having its opposite ends engaging with a portion of the pump body serves to readily detachably connect the bowl with the body.

The conventional screen 36 and gasket 3l are preferably interposed between the rim of the sediment bowl and the seat 32 so as to form a iluid tight joint between the bowl and the pump body and to effect exclusion of undesired solid particles from the fuel delivered to the pump.

Alongside the downwardly extending branch of the passageway 33 and between it and the diaphragm chamber l2 the body section 'I of the pump is provided with a substantially vertical cylindrical cored passageway 38 opening to the face 32 of the body section 'l over the sediment bowl through an enlarged cored mouth 39 of substantially elliptical shape as clearly shown in Figure 3.

The opposite end of the passageway 38 communicates with the outlet 3l of the pump through a short cored passageway t!! having a smaller diameter than the core 38 so as to denne a shoulder 4l at its juncture therewith.

A substantially elliptical plate 42 is received within the mouth 39 of the passageway and is secured to the body section 'I by means of cap screws 43 passing through holes 44 in the ends of the plate and threading into the body section l alongside the core 38. A gasket 45 is prefpressure stroke of the diaphragm.

The alternate pressure and suction pulsations are manifested in the valve chamber by means of a short transverse passageway 53 leading from the diaphragm chamber to the core 38 medially of its ends.

The particular arrangement of passageways and particularly that of the valve chamber enables the valves of the pump to be readily assembled in their. proper positions merely by their insertion into the core 38 with the plate 32 and sediment bowl 34 removed from the body section I and with the compression spring 49 confined between the valves. The plate 42 is then secured .in the mouth 39 of the valve chamber to retain both valves in their proper positions for replacement or inspection whenever desired. The pump assembly is completed upon securing the sediment bowl in place on its seat 32 of the body section l.

The valves 4'! and 48 are identical and each comprises a substantially cylindrical body portion 55 of a size to slidably fit the core 38, and the body 55 has a valve seat 5E provided by the junction of a bore 5l extending centrally into one end of the valve body with a counterbore 58 opening to the opposite end of the body.

The valve seat 5t thus lies in a pla-ne normal to the common axis of the bores 51 and 58, communication between which is controlled by the valve disc 5l positioned within the bottom of the counterbore 58.

The valve disc '5l is preferably provided with a polygonal shape as indicated in Figure 4 to enable the disc to oat freely toward and from a position engaging its seat 56 during the alternate pressure and suction impulses of the diaphragm and to enable fluid to flow freely therepast when raised off its seat.

The disc 5I is yieldingly urged against its seat by means of a light compression spring 60 conined between the disc and the bottom 6l of a spring cage generally indicated by the numeral 62. The spring cage has its bottom 6| formed as a disc or washer and has a number of spring arms 63 bent to one side thereof substantially perpendicularly to the disctand inserted into-the counterbore 58 for engagement of radially outwardly bent tangs B4 on the; free extremities of the arms within a circumferential: recess 65 cut into the side wall of the. counterbore near the mouth thereof.

The spring: tension of the arms B3 is such that their free ends must be flexed radially inwardly for entrance to the counterborev and so that the same are capable of expanding to engage their tangsy Miwithin the recess I It will be apparent, therefore, that each of the valves` constitutes a unitA capablev of being made in a subassembly operation, and that al -pair of suchvalves constitute a compact and readily assembled valve unit for the fuel pump of this invention.

From the foregoing description taken in connection with the accompanying drawings, it will be readily apparent to those skilled in the art that the fuel pump of this invention combines simplicity of design with ease of assembly and disassembly to enable its manufacture at relatively low cost.

What I claim as my invention is:

l. In a pump of the character described: a pump body; a fluid passageway in the body having an inlet and an outlet and having a valve chamber interposed therebetween; means in the pump body providing for alternately subjectingr the valve chamber to reduced and increased pressure in the suction and pressure strokes of the pump respectively; a pair of check valves in said valve chamber for controlling fluid flow from the inlet to the outlet of said passageway, the movable element on one of said valves responding only to reduced pressure in the chamber on the suction stroke of the pump to permit fluid to flow into said chamber from the inlet of the passageway, and the movable element of the other of said valves responding only to increased pressure in the chamber so that fluid in the chamber is forced to said outlet on the pressure stroke of the pump; uid seals interposed between said Valves and the ends of the valve chamber for precluding fluid flow past said valves except upon response of the movable elements of the valves to pressure; and means in said valve chamber for holding the check valves in predetermined spaced apart positions within the valve chamber and against the seals at the opposite ends of the chamber.

2. In a pump of a character described: a pump body; a fluid passageway in the body including a valve chamber opening at one end to one side of the pump body to provide an inlet to said passageway, said valve chamber opening at its opposite end into said passageway adjacent to the outlet of said passageway; means in the pump body providing for alternately subjecting the valve chamber to reduced and increased pressure on the suction and pressure strokes of the pump respectively; a pair of check valve units slidably received in said chamber and located adjacent to the ends thereof for controlling kfluid flow through said passageway, one of said valve units opening only in response to reduced pressure in the chamber on the suction stroke of the pump to permit fluid to flow into the inlet end of the chamber and the other of said valve units opening only in response to increased pressure in the chamber on the pressure stroke of the pump so that fluid in the chamber is forced to the outlet end of the passageway; shoulders at the opposite ends of the chamber against which the valve 6 units engage, oneof said shoulders being located at said' side of the body and being detachably secured to the body so as` to enable assembly in and disassembly ofA the valve units from said chamber; and' means interposed between the valve units to hold the same apart at the ends of the valve chamber and against said shoulders.

3'. In a pump of the character described: a pump body having a fluid passageway therein, one section of said fluid passageway being enlarged and constituting a valve chamber, said body having a diaphragm chamber communicated with said valve' chamber at a point substantially medially of' the4 endsof the valve chamber; a diaphragm in said diaphragm chamber by which the valve-y chamber is .alternately subjected. to reduced andi increased pressure on the suction and pressure strokes of the diaphragm respectively; a pair of check valve units slidably received in said valve chamber for controlling fluid flow through said passageway, one of said valve units being adjacent to the inlet end of the valve chamber and opening only in response to reduced pressure within the valve chamber on the suction stroke of the diaphragm to permit fluid to flow into the valve chamber from the inlet of the passageway, and the other of said valve units being located at the opposite end of the valve chamber adjacent to the outlet of the passageway and opening only in response to increased pressure within the valve chamber so that uid in the valve chamber is forced therefrom to the outlet of the passageway on the pressure stroke of the pump; spring means interposed between said valve units for yieldingly holding the same at opposite ends of the valve chamber; and seals between the valve units and the ends of the chamber for precluding fluid flow past said valves except upon response of the movable elements of the valves to pressure.

4. In a pump of the character described: a pump body; a sediment bowl detachably mounted on the pump body with its mouth seated against one face of the body, said body having a fluid passageway the outlet of which opens to the exterior of the body remote from said face thereof, said passageway having an enlarged mouth opening to said face of the body at a point encircled by the sediment bowl and providing a valve chamber inwardly of said mouth thereof; a shoulder at the inner end of the valve chamber; means for alternately subjecting the valve chamber to reduced and increased pressure including a diaphragm; a pair of check valve units slidably received in said valve chamber for controlling fluid flow through the passageway, one of said valve units being adjacent to the mouth of the passageway and opening only in response to reduced pressure in the chamber on the suction stroke of the diaphragm so as to permit fluid in said bowl to flow into the interior of the valve chamber and the other of said valve units being disposed adjacent to the shoulder at the opposite end of the valve chamber and opening only in response to increased pressure within the valve chamber so that fluid within the valve chamber is forced to the outlet of the passageway on the pressure stroke of the diaphragm; a plate detachably secured to the pump body in the mouth of said passageway and providing a shoulder at the inlet side of the valve chamber for readily detachably retaining the valve units assembled within the pump body, said plate having an aperture therein in line with the valve chamber to permit fluid to now from the sediment bowl to the valve chambei' on the suction stroke of the diaphragm; and means within the valve chamber interposed between sad valve units for holding the. same spaced apart and against said shoulders.`

5. In a pump of the character described: a pump body having a fluid passageway therein; means detachably connected with the pump body and forming part of the major pump instrumentalties, said means overlying one side of the pump body; inlet and outlet check valve units in said passageway, each valve unit being insertable and removable from the pump body through a counterbore opening to said side of the body which is Covered by said detachable means forming part of the major pump vinstrumentalites; and retainer means detachably connected with the pump body and located wholly within -the 8 body and at least partly in the counterbore through which each-valve unit is removable from the body for holding said valve units in the body.

WERNER E, ARMSTRONG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

